1 Rock and soil resistivity testing technology
On-site observation and construction method: The distance of A B supply electrode is gradually increased to increase the exploration depth, and the apparent resistivity ρ s at different electrode distances can be measured. It adopts the method of processing and interpretation and adopts on-site mapping to quickly determine the resistivity and divide the lithology. With M N as the abscissa, calculate M N / ρ s, and use M N / ρ s as the ordinate, and draw the relationship diagram between M N / ρ s and M N on the double logarithmic coordinate paper. By plotting and explaining the sounding points in sequence, the resistivity values of the layers at each measuring point can be obtained, and the resistivity values of each layer can be mathematically calculated to obtain the average resistivity value of the stratum. The division of physical properties can be calculated by computer numerical simulation, measuring plate method or other manual interpretation methods.
2 Three-dimensional direct current method
The construction adopts one-time pole distribution and multi-pole distance measurement technology. The two-pole device for three-dimensional direct current exploration and construction mainly introduced in this article is: arranging m measurement lines in the exploration area, each measurement line is arranged with n measurement points (electrodes), and the network density is measured. According to the detection target and its detection depth, in the urban construction and water conservancy and electric power engineering survey, the line distance L = 2-10 meters and the distance D = 2-5 meters are generally selected.
3 Multi resistivity imaging electrical method
On the pre-selected measuring lines and measuring points, tens or even hundreds of electrodes are arranged at the same time; then they are connected to the special electrode conversion device with a multi-core cable; the latter can be measured by the instrument according to the instructions of the operator Program control combines these electrodes into the specified electrode device and electrode distance, and quickly completes the resistivity method observation of multiple electrode devices and multiple electrode distances on multiple measurement points of the observation profile. Coupled with the corresponding data processing, mapping and interpretation software, the given geological survey task can be completed in time.